Capacitor with high dielectric constant materials and method of making

ABSTRACT

Stabilized capacitors and DRAM cells using high dielectric constant oxide dielectric materials such as Ta 2 O 5  and Ba x Sr (1−x) TiO 3 , and methods of making such capacitors and DRAM cells are provided. A preferred method includes providing a conductive oxide electrode, depositing a first layer of a high dielectric constant oxide dielectric material on the conductive oxide electrode, oxidizing the conductive oxide electrode and the first layer of the high dielectric constant oxide dielectric material under oxidizing conditions, depositing a second layer of the high dielectric constant oxide dielectric material on the first layer of the dielectric, and depositing an upper layer electrode on the second layer of the high dielectric constant oxide dielectric material.

BACKGROUND OF THE INVENTION

[0001] This invention relates generally to capacitors, and moreparticularly to capacitors made with oxide dielectrics having highdielectric constants but with reduced leakage current, and to methods ofmaking such capacitors and their incorporation into DRAM cells.

[0002] The increase in memory cell density in DRAMs presentssemiconductor chip designers and manufacturers with the challenge ofmaintaining sufficient storage capacity while decreasing cell area. Oneway of increasing cell capacitance is through cell structure techniques,including three dimensional cell capacitors. The continuing drive todecrease size has also led to consideration of materials with higherdielectric constants for use in capacitors. Dielectric constant is avalue characteristic of a material and is proportional to the amount ofcharge that can be stored in a material when the material is interposedbetween two electrodes. Promising dielectric materials includeBa_(x)Sr_((1−x))TiO₃ (“BST”), BaTiO₃, SrTiO₃, PbTiO₃, Pb(Zr,Ti)O₃(“PZT”), (Pb,La)(Zr,Ti)O₃ (“PLZT”), (Pb,La)TiO₃ (“PLT”), KNO₃, Nb₂O₅,Ta₂O₅, and LiNbO₃, all of which have high dielectric constants makingthem particularly desirable for use in capacitors. However, the use ofthese materials has been hampered by their incompatability with currentprocessing techniques and their leakage current characteristics.

[0003] Attempts have been made to overcome the problems associated withthe use of Ta₂O₅. For example, U.S. Pat. No. 5,768,248 to Schuegrafinvolves the deposition of a dielectric nitride layer after the removalof an oxide layer on the capacitor plate. A Ta₂O₅ dielectric layer isthen deposited, followed by a second nitride layer. The nitride layerrestricts oxidation of the inner capacitor plate during the annealing ofthe Ta₂O₅ layer. In U.S. Pat. No. 5,814,852 to Sandhu et al., aprimarily amorphous diffusion barrier layer is deposited on the Ta₂O₅dielectric layer.

[0004] While these techniques have been successful, there remains a needfor improved processes for incorporating high dielectric constant oxidedielectrics in capacitor constructions and for capacitors containingthese materials.

SUMMARY OF THE INVENTION

[0005] The present invention meets these needs by providing a stabilizedcapacitor having improved leakage current characteristics using highdielectric constant oxide dielectric materials, and methods of makingsuch capacitors. By “high dielectric constant oxide dielectric”materials we mean oxides of barium, titanium, strontium, lead,zirconium, lanthanum, and niobium, including, but not limited toBa_(x)Sr_((1−x))TiO₃ (“BST”), BaTiO₃, SrTiO₃, Ta₂O₅, Nb₂O₅, PbTiO₃,Pb(Zr,Ti)O₃ (“PZT”), (Pb,La)(Zr,Ti)O₃ (“PLZT”), (Pb,La)TiO₃ (“PLT”),KNO₃, and LiNbO₃ and having a dielectric constant of at least about 20.

[0006] In accordance with one aspect of the present invention, themethod includes providing a conductive oxide electrode, depositing afirst layer of a high dielectric constant oxide dielectric material ontothe conductive oxide electrode, oxidizing the conductive oxide electrodeand the first layer of the high dielectric constant oxide dielectricmaterial, depositing a second layer of the high dielectric constantoxide dielectric material onto the first layer of the conductive oxideelectrode, and depositing an upper layer electrode onto the second layerof the high dielectric constant oxide dielectric material. Preferably,the upper layer electrode comprises a conductive oxide.

[0007] The high dielectric constant oxide dielectric material isselected from the group consisting of Ba_(x)Sr_((1−x))TiO3, BaTiO₃,SrTiO₃, Ta₂O₅, Nb₂O₅, PbTiO₃, Pb(Zr,Ti)O₃, (Pb,La)(Zr,Ti)O₃,(Pb,La)TiO₃, KNO₃, and LiNbO₃, and preferably comprises either Ta₂O₅ orBa_(x)Sr_((1−x))TiO₃. The high dielectric constant oxide dielectricmaterial is preferably oxidized using a gas plasma treatment which isperformed using an oxidizing gas such as, for example, O₂ and O₃, at atemperature in the range of from about 250° to about 500° C.

[0008] The upper layer electrode may be oxidized, preferably also usinga plasma treatment in an oxidizing environment at a temperature in therange of from about 250° to about 500° C. Alternatively, a gas permeableelectrode may be deposited on the upper layer electrode. In this case,the upper layer electrode is preferably oxidized by annealing underoxidizing conditions at a temperature in the range of from about 350° toabout 500° C., and more preferably from about 400° to about 475° C. Thegas permeable electrode preferably comprises platinum.

[0009] When the high dielectric constant dielectric material is Ta₂O₅,the second layer of Ta₂O₅ in the capacitor structure is preferablyoxidized during fabrication. A number of oxidation methods can be used,including, but not limited to, treatment in an oxidizing gas selectedfrom the group consisting of O₂ and O₃ at a temperature in the range offrom about 300° to about 500° C., furnace oxidation at a temperatureless than about 700° C. in an atmosphere containing a gas selected fromthe group consisting of O₂ and N₂O, and rapid thermal oxidation at atemperature of less than about 700° C. in an atmosphere containing anoxidizing gas selected from the group consisting of O₂ and N₂O.

[0010] If the use of crystalline Ta₂O₅ is desired, the second layer ofthe Ta₂O₅ dielectric can be crystallized before depositing the upperelectrode. The Ta₂O₅ dielectric can be crystallized by heating thedielectric material at a temperature greater than about 700° C. in aninert atmosphere such as nitrogen or argon. The crystallization andoxidation steps may be performed simultaneously by heating the materialat a temperature greater than about 700° C. in an atmosphere containingO₂ and N₂O.

[0011] When the dielectric material is Ba_(x)Sr_((1−x))TiO₃, where xis >0 and <1, the first layer of the Ba_(x)Sr_((1−x))TiO₃ dielectric ispreferably deposited at a temperature of less than about 650° C., andmore preferably in the range of from about 400° to about 500° C. Thesecond layer of the Ba_(x)Sr_((1−x))TiO₃ dielectric material ispreferably deposited at a temperature in the range of from about 550 toabout 600° C.

[0012] The conductive oxide electrode and the upper layer electrodespreferably comprise RuO_(x) or IrO_(x), where x is >0 and <2. WhenRuO_(x) is used as the oxide electrode, the surface of the oxideelectrode may be oxidized prior to depositing the first layer of thehigh dielectric constant dielectric material. The oxidation may becarried out at a temperature in the range of from about 400° to about475° C. in an atmosphere containing an oxidizing gas selected from thegroup consisting of O₂, O₃, and N₂O.

[0013] Another aspect of the present invention is a capacitor comprisingan oxidized conductive oxide electrode, an oxidized first layer of ahigh dielectric constant oxide dielectric material adjacent the oxidizedconductive oxide electrode, a second layer of the high dielectricconstant oxide dielectric material adjacent the first layer of the highdielectric constant oxide dielectric material, and an upper layerelectrode adjacent the second layer of the high dielectric constantoxide dielectric material. The oxidized conductive oxide electrode andthe oxidized first layer of the high dielectric constant oxidedielectric material are oxidized prior to the deposition of the secondlayer of the high dielectric constant oxide material.

[0014] The first layer of the high dielectric constant oxide dielectricmaterial preferably has a thickness of between about 20 and about 50 Å.The high dielectric constant oxide dielectric material is preferablyselected from Ta₂O₅ and Ba_(x)Sr_((1−x))TiO₃. The oxidized conductiveoxide electrode and the upper layer electrode are preferably comprisedof RuO_(x) and IrO_(x). The capacitor can include a gas permeableelectrode, preferably comprising platinum, adjacent to the topelectrode.

[0015] Another aspect of the present invention is a DRAM cell and methodof making it. In a preferred form, the method comprises providing aconductive oxide electrode, depositing a first layer of a highdielectric constant oxide dielectric material on said conductive oxideelectrode, oxidizing said conductive oxide electrode and said firstlayer of said high dielectric constant oxide dielectric material underoxidizing conditions, depositing a second layer of said high dielectricconstant oxide dielectric material on said first layer of said highdielectric constant oxide dielectric material, depositing an upper layerelectrode on said second layer of said high dielectric constant oxidedielectric material, providing a field effect transistor having a pairof source/drain regions, electrically connecting one of saidsource/drain regions with said conductive oxide electrode andelectrically connecting the other of said source/drain regions with abit line.

[0016] Accordingly, it is a feature of the present invention to providea stabilized capacitor having improved leakage current characteristicsusing high dielectric constant oxide dielectric materials, theirincorporation into DRAM cells, and methods of making such capacitors.These, and other features and advantages of the present invention, willbecome apparent from the following detailed description, theaccompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a diagrammatic fragmentary sectional view of asemiconductor substrate fragment made according to one embodiment of thepresent invention;

[0018]FIG. 2 is a diagrammatic fragmentary sectional view of analternative embodiment of a semiconductor substrate fragment madeaccording to the present invention; and

[0019]FIG. 3 is a diagrammatic fragmentary sectional view of anotherembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] As shown in FIG. 1, a fragmentary view of a semiconductorsubstrate is indicated generally by reference number 10. As used herein,the term “semiconductor substrate” refers to silicon structuresincluding silicon wafers, silicon structures in the process offabrication, a semiconductor layer, including a semiconductor layer inthe process of fabrication, and the like. The semiconductor substrate 10includes a bulk silicon substrate 12 with a conductive diffusion area 14formed therein. An insulating layer 16, typically a borophososilicateglass (BPSG), is provided over substrate 12. There is a contact opening18 formed in the insulating layer 16 to diffusion area 14. A conductivematerial 20 fills contact opening 18 forming an electrically conductiveplug, with conductive material 20 and oxide layer 16 having beenplanarized using conventional techniques. Conductive material 20 can beany suitable material, such as, for example, tungsten or conductivelydoped polysilicon. A barrier layer (not shown) of a material such asTiAlN may be present at the top of the plug.

[0021] The plug of conductive material 20 can be produced by initiallyforming conductively doped polysilicon to completely fill opening 18.The polysilicon layer can then be etched back using wet or dry etchprocesses, or by chemical-mechanical polishing (CMP) such that allconductive material has been removed from the upper surface ofinsulating layer 16. Preferably, the removal technique causes a slightrecess of conductive material 20 within opening 18.

[0022] A capacitor 22 is provided on insulating layer 16 and plug 20,with conductive plug 20 constituting a node to which an electricalconnection to capacitor 22 is made. Capacitor 22 comprises an oxideelectrode 24 which is electrically conductive and has been provided andpatterned over plug 20. Examples of preferred materials for electrode 24include, but are not limited to, RuO_(x) and IrO_(x). Oxide electrodes,either as deposited or after crystallization by annealing in a nitrogenatmosphere, are mostly oxygen-deficient.

[0023] One example of a process for depositing oxide electrode 24 is todeposit RuO_(x) using chemical vapor deposition (CVD) of a metalorganicprecursor containing ruthenium. Typically, this process would be carriedout in a reaction chamber at a pressure of about 1 Torr and atemperature of from about 150° to about 200° C. using appropriate gasflow rates for the metalorganic precursor.

[0024] A thin layer of a high dielectric constant oxide dielectricmaterial 28 is on oxide electrode 24. The high dielectric constant oxidedielectric material is preferably either Ta₂O₅ or Ba_(x)Sr_((1−x))TiO₃.Layer 28 is preferably between about 20 and about 50 Å thick. When Ta₂O₅is the dielectric material, layer 28 is preferably between about 20 andabout 30 Å thick. When Ba_(x)Sr_((1−x))TiO₃ is the dielectric, layer 28is preferably between about 40 and 50 Å thick. A second layer of highdielectric constant oxide dielectric material 30 is on first layer 28 atthe desired thickness.

[0025] One example of a process for depositing a high dielectricconstant oxide dielectric material such as Ba_(x)Sr_((1−x))TiO₃ includesusing CVD techniques and metalorganic precursors. Typically, suchmetalorganic precursors would be flowed into a reactor at an appropriaterate under reduced pressure and elevated temperatures to form thedielectric layers 28 and 30. One advantage of the present invention isthat the second layer 30 is deposited at a lower temperature, asexplained in greater detail below, which improves step coverage forthree dimensional capacitor structures.

[0026] The capacitor structure also includes top layer electrode 32 onsecond layer 30 of the oxide dielectric material. Top electrode layer 32is preferably RuO_(x) or IrO_(x). Top layer electrode 32 is preferablyoxidized, such as by a plasma treatment at low temperatures in oxidizingconditions. Alternatively, the capacitor structure may include a gaspermeable electrode 34, comprised of, for example, platinum, on the toplayer electrode 32. Electrode 34 is permeable to oxygen which permitsoxidation of underlying layer 32 when the capacitor is treated underannealing conditions.

[0027] Capacitor 22 is formed by depositing oxide electrode 24 ontoinsulating layer 16 and plug 20. Then, a thin layer of high dielectricconstant oxide dielectric material 28 is deposited onto oxide electrode24. The stack, including the thin layer of oxide dielectric 28 and theoxide electrode 24, is then oxidized. The oxidation is preferably a gasplasma treatment under oxidizing conditions and is preferably carriedout at a temperature of about 400° C. using a gas containing either O₂or O₃. For example, gas plasma may be formed using microwave power onoxygen or ozone gas sufficient to dissociate the oxygen molecules intoindividual activated atoms. With this step, the thin layer of oxidedielectric 28 and the oxide electrode 24 are oxidized. This provides atleast the surface, and preferably an upper portion of the oxideelectrode, with enough oxygen so that electrode 24 will be stable withthe oxide dielectric layer 28.

[0028] When Ba_(x)Sr_((1−x))TiO₃ is used as the oxide dielectric forlayer 28, the thin layer can be deposited at a temperature in the rangeof from about 400 to about 500° C., which is much less than typicaldeposition temperatures of about 650° C. used in the prior art. The lowtemperature deposition of the Ba_(x)Sr_((1−x))TiO₃ layer improves stepcoverage on three dimensional capacitor structures.

[0029] After oxidation of the partially fabricated capacitor stack, asecond layer of high dielectric constant oxide dielectric material 30 isdeposited on first layer 28 to a desired thickness. This second layer 30of oxide dielectric is then treated as appropriate for the dielectricmaterial permitting optimization of the dielectric properties of thelayer and addressing specific integration issues, such as step coverageissues for Ba_(x)Sr_((1−x))TiO₃, for the capacitor structure.

[0030] When Ta₂O₅ is used as the high dielectric constant oxidedielectric material, the second Ta₂O₅ layer is preferably oxidized. Theoxidation procedure can be performed using known methods, including, butnot limited to, plasma treatment, furnace oxidation, and rapid thermaloxidation(RTO). The plasma oxidation is preferably carried out at about400° C. in an atmosphere containing O₂ or O₃. Either the furnaceoxidation or the RTO can be performed at a temperature of less than 700°C. in an atmosphere containing O₂ or N₂O. These oxidation steps requireless time and/or can be performed at lower temperatures as compared totypical single step deposition processes without plasma treatment,because no oxygen will be lost through diffusion to the bottom oxideelectrode during these treatments. Despite the low-temperature, shorttime re-oxidation conditions, the dielectric properties of thedielectric material will still be acceptably high. For example,amorphous Ta₂O₅ has a permittivity of about 25, and there is lessleakage current. Crystalline Ta₂O₅ has a permittivity of about 40 to 50.These process conditions allow the capacitor to be integrated with thewafer substrate at lower temperatures and under less oxidizingconditions than heretofore possible using prior art techniques.

[0031] If crystalline Ta₂O₅ is used as the dielectric material, itshould be crystallized before the oxidation step. The Ta₂O₅ can becrystallized by heating it at a temperature above about 700° C. in anitrogen atmosphere. The crystalline material can then be oxidized usingthe plasma treatment, furnace oxidation, or RTO techniques, as discussedabove. Alternatively, the oxidation and crystallization steps can beperformed simultaneously by heating the Ta₂O₅ dielectric at atemperature above 700° C. in an atmosphere of oxygen or N₂O. Followingthe crystallization/oxidation step, the dielectric material can befurther oxidized using the above described techniques if needed. Thisadditional oxidation step can be performed at lower temperatures and/orshorter times if the oxidation step followed a separate crystallizationstep.

[0032] When Ba_(x)Sr_((1−x))TiO₃ is used as the high dielectric constantoxide dielectric material, the deposition temperature for applyingsecond layer 30 of dielectric material is between about 550 and about600° C. Again, this is less than the typical deposition temperaturesused to deposit Ba_(x)Sr_((1−x))TiO₃ in the prior art (about 650° C.).The ability to use a lower deposition temperature is believed to be theresult of the first Ba_(x)Sr_((1−x))TiO₃ layer 28 improving nucleationand growth of second layer 30. This prevents oxidation of the barrierlayer/poly plug 20 (e.g., TiAlN/poly plug). The stress of the secondBa_(x)Sr_((1−x))TiO₃ layer which is deposited is also believed to beless using a thin first layer 28. This results in improvements in thedielectric properties (e.g., less thickness dependent permittivity andless dielectric loss) of the dielectric layer. Another advantage ofutilizing first layer 28 is the prevention of haze formation in theBa_(x)Sr_((1−x))TiO₃.

[0033] The top layer electrode 32 is then deposited on the second layerof the oxide dielectric 30. The top electrode layer 32 is preferablyRuO_(x) or IrO_(x) which can be deposited using CVD techniques asdescribed above. Top layer electrode 32 is then oxidized, such as by agas plasma treatment at low temperatures in oxidizing conditions.Alternatively, a permeable electrode 34 is deposited on top layerelectrode 32, which is then annealed in oxidizing conditions. Thepermeable electrode 34 is preferable platinum. Because oxygen can easilydiffuse through platinum, it will oxidize the top layer electrode 32. Inthis way oxygen loss from second layer 30 of the dielectric material totop layer electrode 32 in subsequent high temperature processes isprevented.

[0034]FIG. 2 illustrates an alternative embodiment of the capacitorconstruction and method in accordance with the present invention. Likenumbers from FIG. 1 have been used where appropriate, with differencesindicated by the use of different reference numerals or the use of likenumbers with the suffix “A.” Substrate 10A includes a capacitor 22Awhich differs from the previously described embodiment. When RuO_(x) isused as oxide electrode 24, the upper surface 26 of electrode 24 may beoxidized if desired. As deposited, RuO_(x) films include both RuO and Rumetal phases. The presence of the Ru metal phase causes unstablereactions, e.g., the oxidation of Ru metal to RuO₂ in Ta₂O₅metal-insulator-metal (MIM) processing. This condition is undesirablebecause it deteriorates the oxidation kinetics of Ta₂O₅ and also causesformation of interface defects between RuO_(x) and Ta₂O₅. Therefore, itis beneficial to oxidize the upper surface of RuO_(x) layer 24 prior toTa₂O₅ deposition. This provides a stable RuO_(x)/Ta₂O₅ interface.

[0035] The overall thickness of the RuO_(x) layer should preferably bein the range of between about 50 to about 1000 Å, and more preferablybetween about 100 and about 200 Å. The oxidation should be limited tothe upper surface of the RuO_(x) layer, generally between about thefirst 10 to about 50 Å of thickness. If the oxidation is carried out inthe entire layer, rather than just the surface, the layer has a tendencyto become very rough and disturbed. The oxidation procedure may be alow-temperature annealing for a short time. The oxidation is preferablyperformed at a temperature in the range of between about 400 to about475° C. in an atmosphere of O₂, O₃, or N_(2.)O.

[0036] The oxidation is done at a relatively low temperature becauseRuO₄, which is a vapor, forms at higher temperatures, leading to theloss of material from the surface of the layer. The oxidation can bedone either before or after crystallization of the RuO_(x).Alternatively, rather than depositing a layer of RuO_(x), a layer of Rumetal may be deposited, and then the surface layer oxidized to form alayer of RuO₂.

[0037]FIG. 3 depicts another embodiment of the invention in thefabrication of DRAM circuitry. A semiconductor substrate 40 comprisestwo memory cells, each memory cell including a capacitor 42 and a sharedbit contact 44. Capacitors 42 electrically connect with substratediffusion regions 46 (source/drain regions) through silicide regions 48.For simplicity, capacitors 42 are shown as comprising a first capacitorelectrode 50, a capacitor dielectric 52 comprising a first thin layer ofa high dielectric constant oxide dielectric 52 a and a second layer of ahigh dielectric constant oxide dielectric material 52 b, and a secondcapacitor electrode/cell plate 54. These layers are fabricated of thematerials described above, including conductive oxide electrodematerials and the high dielectric constant oxide dielectric materials.These layers are processed as described above to provide the capacitorstructure of the present invention. A dielectric layer 56 is formed oversecond capacitor plate 54. A bit line 58 is fabricated in electricalconnection with bit contact 44. Word lines 60 are fabricated to enableselective gating of the capacitors relative to bit contact 44.

[0038] While certain representative embodiments and details have beenshown for the purpose of illustrating the invention, it will be apparentto those skilled in the art that various changes in the methods andapparatus disclosed herein may be made without departing from the scopeof the invention, which is defined in the appended claims.

What is claimed is:
 1. A method of forming a capacitor comprisingproviding a conductive oxide electrode, depositing a first layer of ahigh dielectric constant oxide dielectric material on said conductiveoxide electrode, oxidizing said conductive oxide electrode and saidfirst layer of said high dielectric constant oxide dielectric materialunder oxidizing conditions, depositing a second layer of said highdielectric constant oxide dielectric material on said first layer ofsaid high dielectric constant oxide dielectric material, and depositingan upper layer electrode on said second layer of said high dielectricconstant oxide dielectric material.
 2. A method as claimed in claim 1wherein said high dielectric constant oxide dielectric material isoxidized using a gas plasma.
 3. A method as claimed in claim 2 whereinsaid gas plasma is formed from a gas selected from the group consistingof O₂ and O₃.
 4. A method as claimed in claim 2 wherein the gas plasmaoxidation is carried out at a temperature in the range of from about250° to about 500° C.
 5. A method as claimed in claim 1 wherein saidhigh dielectric constant oxide dielectric material is Ta₂O₅.
 6. A methodas claimed in claim 5 wherein said high dielectric constant oxidedielectric material is amorphous Ta₂O₅.
 7. A method as claimed in claim5 wherein said high dielectric constant oxide dielectric material iscrystalline Ta₂O₅.
 8. A method of forming a capacitor comprisingproviding a conductive oxide electrode, depositing a first layer of ahigh dielectric constant oxide dielectric material on said conductiveoxide electrode, oxidizing said conductive oxide electrode and saidfirst layer of said high dielectric constant oxide dielectric materialunder oxidizing conditions, depositing a second layer of said highdielectric constant oxide dielectric material on said first layer ofsaid high dielectric constant oxide dielectric material, depositing anupper layer electrode on said second layer of said high dielectricconstant oxide dielectric material, and oxidizing said upper layerelectrode under oxidizing conditions.
 9. A method as claimed in claim 8wherein said upper layer electrode is oxidized using a gas plasma.
 10. Amethod as claimed in claim 9 wherein said gas plasma oxidation iscarried out at a temperature in the range of from about 250° to about500° C.
 11. A method of forming a capacitor comprising providing aconductive oxide electrode, depositing a first layer of a highdielectric constant oxide dielectric material on said conductive oxideelectrode, oxidizing said conductive oxide electrode and said firstlayer of said high dielectric constant oxide dielectric material underoxidizing conditions, depositing a second layer of said high dielectricconstant oxide dielectric material on said first layer of said highdielectric constant oxide dielectric material, depositing an upper layerelectrode on said second layer of said high dielectric constant oxidedielectric material, depositing a gas permeable electrode on said upperlayer electrode, and oxidizing said upper layer electrode.
 12. A methodas claimed in claim 11 wherein said gas permeable electrode comprisesplatinum.
 13. A method as claimed in claim 11 wherein said upper layerelectrode is oxidized by annealing under oxidizing conditions.
 14. Amethod as claimed in claim 13 wherein said upper electrode is annealedat a temperature in the range of from about 350° to about 500° C.
 15. Amethod of forming a capacitor comprising providing a conductive oxideelectrode, depositing a first layer of a high dielectric constant oxidedielectric material comprising Ta₂O₅ on the conductive oxide electrode,oxidizing said conductive oxide electrode and said first layer of saidhigh dielectric constant oxide dielectric material under oxidizingconditions, depositing a second layer of said high dielectric constantoxide dielectric material on said first layer of said high dielectricconstant oxide dielectric material, oxidizing said second layer of saidhigh dielectric constant oxide dielectric material, and depositing anupper layer electrode on said second layer of said high dielectricconstant oxide dielectric material.
 16. A method as claimed in claim 15wherein said second layer of said high dielectric constant oxidedielectric material is oxidized using a gas plasma.
 17. A method asclaimed in claim 16 wherein said gas plasma is formed using a gasselected from the group consisting of O₂ and O₃.
 18. A method as claimedin claim 16 wherein said gas plasma oxidation is carried out at atemperature in the range of from about 300° to about 700° C.
 19. Amethod as claimed in claim 15 wherein said second layer of said highdielectric constant oxide dielectric material is oxidized in a furnace.20. A method as claimed in claim 19 wherein the furnace oxidation isperformed at a temperature of less than about 700° C.
 21. A method asclaimed in claim 19 wherein the furnace oxidation uses a gas selectedfrom the group consisting of O₂ and N₂O.
 22. A method as claimed inclaim 15 wherein said second layer of said high dielectric constantoxide dielectric material is oxidized by rapid thermal oxidation.
 23. Amethod as claimed in claim 22 wherein the rapid thermal oxidation isperformed at a temperature of less than about 700° C.
 24. A method asclaimed in claim 22 wherein the oxidation is performed in the presenceof a gas selected from the group consisting of O₂ and N₂O.
 25. A methodas claimed in claim 15 further comprising crystallizing said secondlayer of said high dielectric constant oxide dielectric material priorto depositing said upper electrode.
 26. A method as claimed in claim 25wherein said second layer of said high dielectric constant oxidedielectric material is crystallized by heating said high dielectricconstant oxide dielectric material at a temperature greater than about700° C. in an inert atmosphere.
 27. A method as claimed in claim 25wherein said second layer of said high dielectric constant oxidedielectric material is crystallized and oxidized by heating said highdielectric constant oxide dielectric material at a temperature greaterthan about 700° C. in an atmosphere containing a gas selected from thegroup consisting of O₂ and N₂O.
 28. A method of forming a capacitorcomprising providing a conductive oxide electrode, depositing a firstlayer of a dielectric material comprising Ta₂O₅ on said conductive oxideelectrode, treating said conductive oxide electrode and said dielectricmaterial under oxidizing conditions, depositing a second layer of adielectric material comprising Ta₂O₅ on said first layer of saiddielectric material, oxidizing said second layer of said dielectricmaterial, crystallizing said second layer of said dielectric material,and depositing an upper layer electrode on said second layer of saiddielectric material.
 29. A method as claimed in claim 28 wherein saidsecond layer of said dielectric material is crystallized by heating at atemperature of greater than about 700° C. in an inert atmosphere.
 30. Amethod as claimed in claim 28 wherein said second layer of saiddielectric material is crystallized and oxidized by heating at atemperature of greater than about 700° C. in an atmosphere containing agas selected from the group consisting of O₂ and N₂O.
 31. A method asclaimed in claim 28 wherein said second layer of said dielectricmaterial is oxidized by a gas plasma.
 32. A method as claimed in claim31 wherein said gas plasma oxidation is carried out in a gas selectedfrom the group consisting of O₂ and O₃.
 33. A method as claimed in claim31 wherein said gas plasma oxidation is carried out at a temperature inthe range of from about 300° to about 700° C.
 34. A method as claimed inclaim 28 wherein said second layer of said dielectric material isoxidized in a furnace.
 35. A method as claimed in claim 34 wherein thefurnace oxidation is carried out at a temperature less than about 700°C.
 36. A method as claimed in claim 34 wherein the furnace oxidation iscarried out in an atmosphere containing a gas selected from the groupconsisting of O₂ and N₂O.
 37. A method as claimed in claim 28 whereinsaid second layer of said dielectric material is oxidized by rapidthermal oxidation.
 38. A method as claimed in claim 37 wherein saidrapid thermal oxidation is carried out at a temperature of less thanabout 700° C.
 39. A method as claimed in claim 37 wherein said rapidthermal oxidation is carried out in an atmosphere containing a gasselected from the group consisting of O₂ and N₂O.
 40. A method offorming a capacitor comprising providing a conductive oxide electrodeselected from the group consisting of RuO_(x) and IrO_(x), depositing afirst layer of a dielectric material selected from the group consistingof Ta₂O₅ and Ba_(x)Sr_((1−x))TiO₃ on said conductive oxide electrode,oxidizing said conductive oxide electrode and said first layer of saiddielectric material with a gas plasma, depositing a second layer of saiddielectric material on said first layer of said dielectric material,depositing an upper layer electrode on said second layer of saiddielectric material, and oxidizing said upper layer electrode.
 41. Amethod as claimed in claim 40 wherein said conductive oxide electrodeand said first layer of said dielectric material are oxidized using agas selected from the group consisting of O₂ and O₃.
 42. A method asclaimed in claim 40 wherein the oxidation is carried out at atemperature in the range of from about 250° to about 500° C.
 43. Amethod as claimed in claim 40 wherein said upper layer electrode isoxidized using a second gas plasma in an oxidizing environment.
 44. Amethod as claimed in claim 43 wherein the oxidation of said upper layerelectrode is carried out at a temperature in the range of from about250° to about 500° C.
 45. A method as claimed in claim 40 wherein saidupper layer electrode is selected from the group consisting of RuO_(x)and IrO_(x).
 46. A method as claimed in claim 40 wherein said conductiveoxide electrode comprises RuO_(x) and said first layer of saiddielectric material comprises Ta₂O₅.
 47. A method as claimed in claim 46further comprising oxidizing the surface of said conductive oxideelectrode prior to depositing said first layer of said dielectricmaterial.
 48. A method as claimed in claim 47 wherein the surface ofsaid conductive oxide electrode is oxidized at a temperature in therange of from about 400° to about 475° C.
 49. A method as claimed inclaim 47 wherein the surface of said conductive oxide electrode isoxidized in an atmosphere containing a gas selected from the groupconsisting of O₂, O₃, and N₂O.
 50. A method of forming a capacitorcomprising providing a conductive oxide electrode selected from thegroup consisting of RuO_(x) and IrO_(x), depositing a first layer of adielectric material selected from the group consisting of Ta₂O₅ andBa_(x)Sr_((1−x))TiO₃ on said conductive oxide electrode, oxidizing saidconductive oxide electrode and said first layer of said dielectricmaterial using a gas plasma under oxidizing conditions, depositing asecond layer of said dielectric material on said first layer of saiddielectric material, oxidizing said second layer of said dielectricmaterial, depositing an upper layer electrode on said second layer ofsaid dielectric material, and oxidizing said upper layer electrode. 51.A method as claimed in claim 50 wherein said second layer of saiddielectric material is oxidized with a gas plasma.
 52. A method asclaimed in claim 51 wherein said gas plasma is formed from a gasselected from the group consisting of O₂ and O₃.
 53. A method as claimedin claim 51 wherein said oxidation is carried out at a temperature inthe range of from about 250° to about 500° C.
 54. A method as claimed inclaim 50 wherein said second layer of said dielectric material isoxidized in a furnace.
 55. A method as claimed in claim 54 wherein saidfurnace oxidation is carried out at a temperature of less than about700° C.
 56. A method as claimed in claim 54 wherein said furnaceoxidation is carried out in an atmosphere comprising a gas selected fromthe group consisting of O₂ and N₂O.
 57. A method as claimed in claim 50wherein said second layer of said dielectric material is oxidized byrapid thermal oxidation.
 58. A method as claimed in claim 57 wherein theoxidation is carried out at a temperature less than about 700° C.
 59. Amethod as claimed in claim 57 wherein the oxidation is carried out in anatmosphere containing a gas selected from the group consisting of O₂ andN₂O.
 60. A method as claimed in claim 50 wherein said upper layerelectrode is oxidized using a gas plasma under oxidizing conditions. 61.A method as claimed in claim 60 wherein the oxidation is carried out ata temperature in the range of from about 250° to about 500° C.
 62. Amethod as claimed in claim 50 further comprising depositing a gaspermeable electrode on said upper layer electrode prior to oxidizingsaid upper layer electrode.
 63. A method as claimed in claim 62 whereinsaid gas permeable electrode comprises platinum.
 64. A method as claimedin claim 62 wherein said upper layer electrode is oxidized by annealingunder oxidizing conditions.
 65. A method as claimed in claim 64 whereinthe annealing is carried out at a temperature in the range of from about350° to about 500° C.
 66. A method of forming a capacitor comprisingproviding a conductive oxide electrode, depositing a first layer of aBa_(x)Sr_((1−x))TiO₃ dielectric material on said conductive oxideelectrode, oxidizing said conductive oxide electrode and said firstlayer of said dielectric material with a gas plasma under oxidizingconditions, depositing a second layer of said dielectric material onsaid first layer of said dielectric material, depositing an upper layerelectrode on said second layer of said dielectric material, andoxidizing said upper layer electrode.
 67. A method as claimed in claim66 wherein said first layer of said dielectric material is deposited ata temperature of less than about 650° C.
 68. A method as claimed inclaim 66 wherein said first layer of said dielectric material isdeposited at a temperature in the range of from about 400° to about 500°C.
 69. A method as claimed in claim 66 wherein said conductive oxideelectrode is selected from the group consisting of RuO_(x) and IrO_(x).70. A method as claimed in claim 66 wherein said first layer of saiddielectric material is deposited at a temperature of less than about650° C.
 71. A method as claimed in claim 66 wherein said second layer ofsaid dielectric material is deposited at a temperature in the range offrom about 550° to about 600° C.
 72. A method as claimed in claim 66wherein said upper layer electrode is selected from the group consistingof RuO_(x) and IrO_(x).
 73. A method of forming a capacitor comprisingproviding a conductive oxide electrode depositing a first layer of ahigh dielectric constant oxide dielectric material on said conductiveoxide electrode, oxidizing said conductive oxide electrode and saidfirst layer of said high dielectric constant oxide dielectric materialunder oxidizing conditions, depositing a second layer of said highdielectric constant oxide dielectric material on said first layer ofsaid high dielectric constant oxide dielectric material, and depositingan upper layer electrode on said second layer of high dielectricconstant oxide dielectric material.
 74. A method as claimed in claim 73wherein said high dielectric constant oxide dielectric material isselected from the group consisting of Ta₂O₅ and Ba_(x)Sr_((1−x))TiO₃.75. A method as claimed in claim 73 wherein said conductive oxideelectrode is selected from the group consisting of RuO_(x) and IrO_(x).76. A method as claimed in claim 73 wherein said upper layer electrodeis selected from the group consisting of RuO_(x) and IrO_(x).
 77. Amethod as claimed in claim 73 wherein said high dielectric constantoxide dielectric material is oxidized using a gas plasma.
 78. A methodas claimed in claim 77 wherein said oxidation is carried out in anatmosphere containing a gas selected from the group consisting of O₂ andO₃.
 79. A method as claimed in claim 77 wherein the oxidation is carriedout at a temperature in the range of from about 250° to about 500° C.80. A capacitor comprising an oxidized conductive oxide electrode, anoxidized first layer of a high dielectric constant oxide dielectricmaterial adjacent said oxidized conductive oxide electrode, a secondlayer of said high dielectric constant oxide dielectric materialadjacent said first layer of said high dielectric constant oxidedielectric material, and an upper layer electrode adjacent said secondlayer of said high dielectric constant oxide dielectric material,wherein said oxidized conductive oxide electrode and said oxidized firstlayer of said high dielectric constant oxide dielectric material areoxidized prior to depositing said second layer of said high dielectricconstant oxide dielectric material oxide dielectric.
 81. A capacitor asclaimed in claim 80 wherein said high dielectric constant oxidedielectric material is selected from the group consisting of Ta₂O₅ andBa_(x)Sr_((1−x))TiO₃.
 82. A capacitor as claimed in claim 80 whereinsaid oxidized conductive oxide electrode is selected from the groupconsisting of RuO_(x) and IrO_(x).
 83. A capacitor as claimed in claim80 wherein said upper layer electrode is selected from the groupconsisting of RuO_(x) and IrO_(x).
 84. A capacitor as claimed in claim80 further comprising a gas permeable electrode adjacent said upperlayer electrode.
 85. A capacitor as claimed in claim 84 wherein said gaspermeable electrode comprises platinum.
 86. A capacitor as claimed inclaim 80 wherein said first layer of said high dielectric constant oxidedielectric material is between about 20 and about 50 Å thick.
 87. Acapacitor comprising an oxidized conductive oxide electrode selectedfrom the group consisting of RuO_(x) and IrO_(x), an oxidized firstlayer of a high dielectric constant oxide dielectric material adjacentto said oxidized conductive oxide layer, a second layer of said highdielectric constant oxide dielectric material adjacent to said firstlayer of said high dielectric constant oxide dielectric material, and anupper layer electrode selected from the group consisting of RuO_(x) andIrO_(x) adjacent said second layer of said high dielectric constantoxide dielectric material, wherein said oxidized conductive oxideelectrode and said oxidized first layer of said high dielectric constantoxide dielectric material are oxidized prior to the deposition of saidsecond layer of said high dielectric constant oxide dielectric material.88. A capacitor as claimed in claim 87 wherein said high dielectricconstant oxide dielectric material is selected from the group consistingof Ta₂O₅ and Ba_(x)Sr_((1−x))TiO₃.
 89. A capacitor as claimed in claim87 wherein said first layer of said high dielectric constant oxidedielectric material is between about 20 and about 50 Å thick.
 90. Acapacitor comprising an oxidized conductive oxide electrode, an oxidizedfirst layer of a high dielectric constant oxide dielectric materialselected from the group consisting of Ta₂O₅ and Ba_(x)Sr_((1−x))TiO₃adjacent said oxidized conductive oxide electrode, a second layer ofsaid high dielectric constant oxide dielectric material adjacent saidfirst layer of said high dielectric constant oxide dielectric material,and an upper layer electrode adjacent said second layer of said highdielectric constant oxide dielectric material, and wherein said oxidizedconductive oxide electrode and said oxidized first layer of said highdielectric constant oxide dielectric material are oxidized prior to thedeposition of said second layer of said high dielectric constant oxidedielectric material.
 91. A capacitor as claimed in claim 90 wherein saidoxidized conductive oxide electrode is selected from the groupconsisting of RuO_(x) and IrO_(x).
 92. A capacitor as claimed in claim90 wherein said upper layer electrode is selected from the groupconsisting of RuO_(x) and IrO_(x).
 93. A capacitor as claimed in claim90 further comprising a gas permeable electrode adjacent to said upperlayer electrode.
 94. A capacitor as claimed in claim 93 wherein said gaspermeable electrode comprises platinum.
 95. A capacitor as claimed inclaim 90 wherein said first layer of said high dielectric constant oxidedielectric material is between about 20 and about 50 Å thick.
 96. Acapacitor comprising an oxidized conductive oxide electrode selectedfrom the group consisting of RuO_(x) and IrO_(x), an oxidized firstlayer of a high dielectric constant oxide dielectric material selectedfrom the group consisting of Ta₂O₅ and Ba_(x)Sr_((1−x))TiO₃ adjacent tosaid oxidized conductive oxide layer; a second layer of high dielectricconstant oxide dielectric material adjacent to said first layer of saidhigh dielectric constant oxide dielectric material, and an upper layerelectrode selected from the group consisting of RuO_(x) and IrO_(x)adjacent to said second layer of said high dielectric constant oxidedielectric material, and wherein said oxidized conductive oxideelectrode and said oxidized first layer of said high dielectric constantoxide dielectric material are oxidized prior to the deposition of saidsecond layer of said high dielectric constant oxide dielectric material.97. A capacitor as claimed in claim 96 further comprising a gaspermeable electrode adjacent said upper layer electrode.
 98. A capacitoras claimed in claim 97 wherein said gas permeable electrode comprisesplatinum.
 99. A capacitor as claimed in claim 96 wherein said firstlayer of said high dielectric constant oxide dielectric material isbetween about 20 and about 50 Å thick.
 100. A method of forming a DRAMcell comprising providing a conductive oxide electrode, depositing afirst layer of a high dielectric constant oxide dielectric material onsaid conductive oxide electrode, oxidizing said conductive oxideelectrode and said first layer of said high dielectric constant oxidedielectric material under oxidizing conditions, depositing a secondlayer of said high dielectric constant oxide dielectric material on saidfirst layer of said high dielectric constant oxide dielectric material,depositing an upper layer electrode on said second layer of said highdielectric constant oxide dielectric material, providing a field effecttransistor having a pair of source/drain regions, electricallyconnecting one of said source/drain regions with said conductive oxideelectrode and electrically connecting the other of said source/drainregions with a bit line.
 101. A method as claimed in claim 100 whereinsaid high dielectric constant oxide dielectric material is oxidizedusing a gas plasma.
 102. A method as claimed in claim 101 wherein saidgas plasma is formed from a gas selected from the group consisting of O₂and O₃.
 103. A method as claimed in claim 101 wherein the gas plasmaoxidation is carried out at a temperature in the range of from about250° to about 500° C.
 104. A method as claimed in claim 100 wherein saidhigh dielectric constant oxide dielectric material is Ta₂O₅.
 105. Amethod as claimed in claim 104 wherein said high dielectric constantoxide dielectric material is amorphous Ta₂O₅.
 106. A method as claimedin claim 104 wherein said high dielectric constant oxide dielectricmaterial is crystalline Ta₂O₅.